Method for determining the fill state in a tank utilizing ultrasonic waves and reference surfaces
First Claim
1. A method for determining a level of a liquid in a tank, the method comprising:
- providing a tank supporting a liquid, the tank defining a tank wall;
providing an ultrasonic level sensor supported by the tank, the ultrasonic level sensor having a transmitter unit and a receiver unit;
emitting, from the transmitter unit an ultrasonic wave;
receiving, at the receiver unit the emitted ultrasonic wave;
providing a calibration component, the calibration component comprising;
a spring segment;
a contact surface pressed fixedly on the tank wall by way of the spring segment; and
at least two reference surfaces for reflection of the ultrasonic wave, a first reference surface is disposed below a second reference surface;
providing a controller in communication with the ultrasonic level sensor;
a) determining, at the controller, a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface;
b) determining, at the controller, a second propagation speed of an ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface;
c) measuring, at the controller, a propagation time of an ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank;
d) selecting, at the controller, the first propagation speed or the second propagation speed depending on a first selection criterion and checking, at the controller, the measured propagation speed as a second selection criterion, wherein the second propagation speed is not selected if the measured propagation time lies outside a time interval corresponding to twice the propagation time to the second reference surface and the first propagation speed was selected for a previous iteration of the method; and
e) computing, at the controller, the level of the liquid with the propagation time measured in step c) and the propagation speed selected in step d).
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Accused Products
Abstract
The disclosure relates to a method for determining a level of a liquid in a tank with an ultrasonic fill state sensor and at least two reference surfaces for reflecting an ultrasonic wave transmitted by the ultrasonic fill state sensor. A first reference surface is arranged below a second reference surface. The method includes determining a first propagation speed of an ultrasonic wave to the first reference surface on a first measurement path and a second propagation speed from the first reference surface to the second reference surface on a second measurement path. The method also includes measuring a propagation time of an ultrasonic wave from the ultrasonic fill state sensor to a liquid level of the liquid in the tank, selecting the first propagation speed or the second propagation speed based on at least one selection criterion, and calculating a fill state using the propagation time measured.
34 Citations
20 Claims
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1. A method for determining a level of a liquid in a tank, the method comprising:
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providing a tank supporting a liquid, the tank defining a tank wall; providing an ultrasonic level sensor supported by the tank, the ultrasonic level sensor having a transmitter unit and a receiver unit; emitting, from the transmitter unit an ultrasonic wave; receiving, at the receiver unit the emitted ultrasonic wave; providing a calibration component, the calibration component comprising; a spring segment; a contact surface pressed fixedly on the tank wall by way of the spring segment; and at least two reference surfaces for reflection of the ultrasonic wave, a first reference surface is disposed below a second reference surface; providing a controller in communication with the ultrasonic level sensor; a) determining, at the controller, a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface; b) determining, at the controller, a second propagation speed of an ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface; c) measuring, at the controller, a propagation time of an ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank; d) selecting, at the controller, the first propagation speed or the second propagation speed depending on a first selection criterion and checking, at the controller, the measured propagation speed as a second selection criterion, wherein the second propagation speed is not selected if the measured propagation time lies outside a time interval corresponding to twice the propagation time to the second reference surface and the first propagation speed was selected for a previous iteration of the method; and e) computing, at the controller, the level of the liquid with the propagation time measured in step c) and the propagation speed selected in step d). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A motor vehicle comprising:
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a tank supporting a liquid and defining a tank wall; an ultrasonic level sensor supported by the tank, the ultrasonic level sensor comprising; a transmitter unit emitting an ultrasonic wave, and a receiver unit receiving the emitted ultrasonic wave; a calibration component comprising; a spring segment; a contact surface pressed fixedly on the tank wall by way of the spring segment; and at least two reference surfaces for reflection of the ultrasonic wave, the at least two reference surfaces include a first reference surface and a second reference surface, wherein the first reference surface is disposed below the second reference surface; and a controller in communication with the ultrasonic level sensor, the controller determines the level of the liquid in the tank by executing the following steps; a) determining a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface; b) determining a second propagation speed of the ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface; c) measuring a propagation time of the ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank; d) selecting the first propagation speed or the second propagation speed depending on a first selection criterion, and checking the measured propagation speed as a second selection criterion, wherein the second propagation speed is not selected if the measured propagation time lies outside a time interval corresponding to twice the propagation time to the second reference surface and the first propagation speed was selected for a previous iteration of the method; and e) computing a level of the liquid with the propagation time measured in step c) and the propagation speed selected in step d). - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for determining a level of a liquid in a tank, the method comprising:
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providing a tank supporting a liquid, the tank defining a tank wall; providing an ultrasonic level sensor supported by the tank, the ultrasonic level sensor having a transmitter unit and a receiver unit; emitting, from the transmitter unit an ultrasonic wave; receiving, at the receiver unit the emitted ultrasonic wave; providing a calibration component, the calibration component comprising; a spring segment; a contact surface pressed fixedly on the tank wall by way of the spring segment; and at least two reference surfaces for reflection of the ultrasonic wave, a first reference surface is disposed below a second reference surface; providing a controller in communication with the ultrasonic level sensor; a) determining, at the controller, a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface; b) determining, at the controller, a second propagation speed of an ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface; c) measuring, at the controller, a propagation time of an ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank; d) selecting, at the controller, the first propagation speed or the second propagation speed depending on a first selection criterion; and e) computing, at the controller, a level with the propagation time measured in step c) and the propagation speed selected in step d) by executing the following substeps; i) computing the level based on the selected propagation speed; ii) checking whether a level which is determined at the second propagation speed corresponds to twice a height of the second reference surface; iii) determining a fluctuation in a second response signal of the second reference surface at the ultrasonic level sensor in a time interval; iv) checking whether the fluctuation in the second response signal exceeds a prespecified limit value; and v) correcting the level which is computed in step i) to the height of the second reference surface when steps ii) and iv) are complete.
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20. A motor vehicle comprising:
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a tank supporting a liquid and defining a tank wall; an ultrasonic level sensor supported by the tank, the ultrasonic level sensor comprising; a transmitter unit emitting an ultrasonic wave, and a receiver unit receiving the emitted ultrasonic wave; a calibration component comprising; a spring segment; a contact surface pressed fixedly on the tank wall by way of the spring segment; and at least two reference surfaces for reflection of the ultrasonic wave, the at least two reference surfaces include a first reference surface and a second reference surface, wherein the first reference surface is disposed below the second reference surface; and a controller in communication with the ultrasonic level sensor, the controller determines the level of the liquid in the tank by executing the following steps; a) determining a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface; b) determining a second propagation speed of the ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface; c) measuring a propagation time of the ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank; d) selecting the first propagation speed or the second propagation speed depending on at least one selection criterion; and e) computing a level with the propagation time measured in step c) and the propagation speed selected in step d) by executing the following subsets; i) computing the level based on the selected propagation speed; ii) checking whether a level which is determined at the second propagation speed corresponds to twice a height of the second reference surface; iii) determining a fluctuation in a second response signal of the second reference surface at the ultrasonic level sensor in a time interval; iv) checking whether the fluctuation in the second response signal exceeds a prespecified limit value; and v) correcting the level which is computed in step i) to the height of the second reference surface when steps ii) and iv) are complete.
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Specification